This invention relates in general to conveyor belt material-transporting containers and in particular to grain cups for use with grain elevators.
One essential category of equipment for the grain and feed industry is bucket elevators. Such elevators are used to move grain from an initial deposit point at or near ground level to a distribution point at some height above ground level. The deposit point may be, for example, where a farmer makes his delivery to a grain elevator and the distribution point may be, for example, the starting point of the grain-processing cycle at the elevator. At the deposit point, the grain is accumulated in a housing through which an endless conveyor belt passes. By providing containers on this endless conveyor belt, the grain is scooped up and carried to a higher point. As a container reaches a top dead center position with respect to the conveyor belt path and begins its downward travel, the grain in the container is discharged into a head portion which is in communication with the distribution point. This discharging of the grain involves a type of throwing action and one important design consideration is how to structure the particular containers to achieve a complete, yet smooth and continuous grain discharge.
Further design considerations involve the capacity of the containers, their durability and the rate at which they can move through the conveyor belt cycle. Due to the fact that the conveyor belt is enclosed by a transport tube, container capacity is constrained by the inside diameter size of this tube. Although the containers could be made deeper to increase their capacity, this may cause failure to completely discharge the grain. A larger container takes longer to empty and the cycle time must be adjusted with container volume considered. Consequently, grain containers of the type described herein must reach a critical balance between such competing factors as material choice, size, conveyor cycle rate and geometry in order to provide the optimal capacity to the elevator, a figure expressed in bushels per hour.
The following listed patents describe various container and elevator bucket designs which have been conceived over the years, and although these designs have been patented, none provide the combination of features which are necessary for an optimal grain cup design.
______________________________________ U.S. Pat. No. Patentee Issue Date ______________________________________ 148,429 Duc, Jr. 3/10/74 180,809 Whittaker 8/08/76 221,207 Avery 11/04/79 2,004,632 Schauer 6/11/35 2,122,036 Lindburg 6/28/38 2,501,229 Lindfors 3/21/50 2,908,375 Hoover et al. 10/13/59 3,381,796 Gregor 5/07/68 1,023,460 Gr. Britain 3/23/66 728,419 Gr. Britain 4/20/55 101,521 Jonckheere 10/01/23 (Switzerland) ______________________________________
Duc, Jr. discloses a part-spherical elevator bucket fabricated of metal and providing a shape wherein the cubic contents is greater in proportion to the amount of material used than with other shapes.
Whittaker discloses an elevator bucket having a greater bulge at the center of the front than at the sides thereby freeing the bucket from a tendency to catch the side of the trough or casing through which it travels.
Avery discloses an elevator bucket fabricated of a single piece of sheet metal and having a flat bottom, curved sides and front and a flat back. The forward edge of the bucket being below the rear edge when the bucket is attached to a conveyor belt.
Schauer discloses a bucket design, and although the intended use is for dredging machines, this design is of interest for its disclosure of a relatively sharp leading edge portion which permits the bucket to "cut" through the material to be excavated.
Lindburg discloses an elevator cup having a plurality of different angular sections, comprising the bottom of the cup, in order to facilitate progressive discharge of the contents.
Lindfors discloses a grain elevator bucket wherein a corner portion of each end is turned inwardly into the bucket in order to provide an air escape path as grain is scooped up.
Hoover et al. discloses a lemon feeder and although this is significantly different art from that of the present invention, this patent is cited for its disclosure of the cup designs. These cups include a front portion arranged as a polyhedral and a bottom surface sloping downwardly from the rear to front.
Gregor discloses a molded pivot bucket for a conveyor wherein the bucket is fabricated as a single integral member out of a synthetic plastic material such as polypropylene.
The first Great Britain patent (No. 1,023,460) discloses an elevator bucket wherein the front portion is curved upwardly and outwardly, and when attached to a conveyor belt, the forward edge is below the rear edge.
The other Great Britain patent (No. 728,419) discloses a bucket for use with an endless conveyor belt wherein the bucket is fabricated from a synthetic resin material and has a raised area on each side panel in order to increase capacity of the bucket.
The Jonckheere patent discloses a container design having a generally rectangular top view and an outwardly flared "U" shape in lateral cross section.
Designs such as that of Duc, Jr. and Avery provide a curved front edge as is required to maximize the usage of the available space within the transporting tube. However, the remainder of the design of these buckets is not suitable to provide a smooth and continuous grain discharge. Similarly, designs such as that of Lindburg and Lindfors provide a more suitable lateral section configuration, but their generally rectangular top view makes them unsuitable for maximizing capacity when the cups must pass through a fixed transport tube. Other important features of an optimal grain cup are that it be designed to flex rather than permanently bend, have a plurality of vent holes to allow free entry of grain, have a specific front portion curvature relative to the vertical in order to create a gentle discharge pattern and that this curvature be continuous to assure discharge of the grain contained in the cup. None of the listed patents disclose all of these features and thus none of the listed patents disclose an optimal grain cup configuration. It is not merely a perfunctory step to mix desirable features from several designs into one and thereby create an optimal cup configuration. Each design feature must be tempered with respect to other criteria and features and only by a balancing of such features can an optimum cup configuration be achieved. The subject invention disclosed herein provides such an optimal balancing.